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/*!
@file
Forward declares `boost::hana::intersection`.
@copyright Louis Dionne 2013-2016
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
*/
#ifndef BOOST_HANA_FWD_INTERSECTION_HPP
#define BOOST_HANA_FWD_INTERSECTION_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Returns the intersection of two sets.
//! @relates hana::set
//!
//! Given two sets `xs` and `ys`, `intersection(xs, ys)` is a new set
//! containing exactly those elements that are present both in `xs` and
//! in `ys`. In other words, the following holds for any object `x`:
//! @code
//! x ^in^ intersection(xs, ys) if and only if x ^in^ xs && x ^in^ ys
//! @endcode
//!
//!
//! @param xs, ys
//! Two sets to intersect.
//!
//!
//! Example
//! -------
//! @include example/intersection.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto intersection = [](auto&& xs, auto&& ys) {
return tag-dispatched;
};
#else
template <typename S, typename = void>
struct intersection_impl : intersection_impl<S, when<true>> { };
struct intersection_t {
template <typename Xs, typename Ys>
constexpr auto operator()(Xs&& xs, Ys&& ys) const;
};
constexpr intersection_t intersection{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_INTERSECTION_HPP
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